This invention relates in general to undercut saws, and more specifically involves an undercut saw with a centrally located height adjustment mechanism.
Undercut saws or flush-cutting saws are used to undercut doors and baseboards, typically about 0.25 inches to 1.75 inches, to provide sufficient space for floor coverings to fit underneath.
Conventional undercut saws use a cutting assembly including an electric rotary motor driving a shaft rotating a flat, circular cutting blade in a horizontal plane. The cutting assembly is held above a guide surface, such as a floor, by a base which provides a large stable skid surface for sliding the saw along the floor. The base includes an inner portion attached to the cutting assembly, horizontal portion extending radially outward therefrom and past the blade circumference, and an outer generally vertical leg portion extending down from the periphery of the horizontal portion to rest on the floor.
The blade is adjusted vertically by adjusting the height of the leg of the base. Typically, the leg comprises includes inner and outer mating vertically telescopic collars. The relative position of the collars determined in a manner such as the inner collar having a plurality of spaced protruding studs, the outer collar having slots for receiving the studs, and a plurality of wing nuts, each attached to a stud for clamping the collars together.
This peripheral adjustment approach has several shortcomings. Notably, it is slow because several fasteners require adjustment. More importantly, using the peripheral adjustments, it is difficult to adjust the height so that the blade is level. The blade is only level if each of the peripheral clamps, e.g. studs and wingnuts, are at the same height. This is not quickly and easily accomplished.
At least one attempt has been made to provide central height adjustment using an angled drive, but this resulted in an awkward, unbalanced device requiring a large triangular base.
Therefore, there has been a need for an undercut saw with improved mechanism that quickly and accurately adjusts the cutting height while maintaining the blade level and does not otherwise detract from the ergonomics of the saw.
This invention is an undercut saw having a central axis and it generally comprises a cutting assembly and a base. The cutting assembly comprises a case, housing an electric motor that drives a shaft upon which a saw blade is mounted to rotate in a plane perpendicular to the central axis. The base supports the cutting assembly above a support surface and comprises a cylindrical sleeve horizontally surrounding the motor case and supporting the case such that the central axis is vertical, a horizontal portion extending radially outward from the sleeve and having a periphery past the blade circumference so as to cover said blade except for an exposed cutting area, and a generally vertical leg portion extending down from the periphery of the horizontal portion and terminating in a foot for resting on the support surface. The case and sleeve are cooperatively adapted such that the case may be selectively moved vertically within the sleeve and retained in the selected position so as to adjust the height of the blade relative to the foot.
In a first preferred embodiment, the case and sleeve include cooperating screw means for moving said case vertically in said sleeve upon rotation of said case relative to said sleeve about the central axis. A line cord departs the motor assembly along the central axis.
Other features and many attendant advantages of the invention will become more apparent upon a reading of the following detailed description together with the drawings wherein like reference numerals refer to like parts throughout.